As semiconductor device is micronized, the use of high dielectric constant insulation film of hafnium oxide film, etc., whose relative dielectric constant is higher than that of silicon oxide film, as the gate insulation film of MIS (Metal Insulator Semiconductor) transistor is noted.
Also as the gate electrode of a MISFET, the use of a metal gate electrode in place of a gate electrode of polysilicon is noted. The use of the metal gate electrode can prevent the generation of a depletion layer in the gate electrode, and the current driving force of the MIS transistor can be improved.
Related reference is as follows:    Japanese Laid-open Patent Publication No. 2009-194352; and    Y. Kamimura et al., “Comprehensive Study of VFB Shift in High-k CMOS-Dipole Formation, Fermi-level Pinning and Oxygen Vacancy Effect-”, IEEE International Electron Meeting, pp. 341-344, 2007.